Preparative chromatography oligonucleotides

FIGURE 15 Preparative displacement chromatography of a 24 mer phosphorothioate oligonucleotide. (Gerstner et a/.,79 with permission from Oxford University Press.) Load 1.2 g (6 mg/mL Cv) column 50 mmD X 100 mmL POROS HQ-M flow rate 150 cm / hr (50 mL/min) mobile phase 100 mM NaCI, 10 mM NaOH, 5% methanol displacer 800 mL of 7 mg/mL dextran sulfate fraction size 14 mL. 

An important advantage of mass spectrometry over other techniques such as electrophoresis or chromatography is its high speed. For instance, the association of MALDI/TOF with automatic preparation of the samples, together with automated acquisition of the spectra, allows the analysis of more than 100 oligonucleotides in 90 min. [172]... 

Other mixtures of oligonucleotides must be fractionated in larger quantities or are too complex to be separated by traditional paper chromatography and electrophoresis. Large quantities (> 1 mg) of material arise in preparative procedures, in nucleotide sequence analysis of nucleic acids which are not radioactively labelled, and in mixtures where the components of interest are present in very small proportions. Column chromatography is widely used in these cases. 

Since the usual ion-exchange resins have very limited use for chromatography of proteins, Peterson and Sober investigated adsorbents derived from cellulose, of which the most useful is DEAE-cellulose. It is prepared by treating a high-purity wood cellulose with 2-chloroethyldiethylamine hydrochloride to give a diethyl-aminoethyl (DEAE) derivative. This material has been used successfully for the fractionation of serum proteins and oligonucleotides. ... 

Ion-exchange chromatography has many clinical applications, including the separation of amino acids, peptides, proteins, nucleotides, oligonucleotides, and nucleic acids. Another important application of ion-exchange chromatography is the separation and removal of inorganic ions from aqueous mixtures. Thus most water purification units used to prepare deionized water for the laboratory contain "mixed-bed columns of cation and anion resins (see Chapter 1). 

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